1. Field of the Invention
The present invention relates to a production method for rotating electric machinery such as motors and generators, and stator coils, and to electric power steering motors. More specifically, the present invention pertains to a production method for a rotating electric machine and stator coils, and an electric power steering motor that are suitable for ones having split stator cores.
2. Description of the Related Art
Two types of rotating electric machines have been conventionally known in which a stator core is split into a plurality of parts and in which coils are concentratedly wound on each tooth. One of these types is, as disclosed in, for example, Japanese Patent Nos. 3355700 and 3430521, a type in which a core back is split into a plurality of core back portions along its circumferential direction, and in which the split core back portions and tooth portions radially projected from the respective split core back portions are integrated into T-shaped core back pieces. The other is, as disclosed in, for example, Japanese Patent No. 2547131 and JP-A-6-133501, a type in which the stator is split into a teeth portion and an annular core back portion.
By splitting the core into a plurality of parts in these manners, tracks necessary for the movement of a nozzle of a coil winding machine can be secured for winding a coil. This improves the alignment property of coils and enables a high coil space factor to be obtained. The splitting of the core further makes it possible to shorten coil ends, which are magnetically inoperative portions, and reduce the shaft length of a rotating electric machine, as well as decrease copper loss. This allows an achievement of the miniaturization of rotating electric machinery and the enhancement of its efficiency. As a result, such core-splitting methods are coming into widespread adoption in rotating electric machinery for automobiles, which are subjected to restrictions on installation space and weight.
Moreover, in order to miniaturize and cost-cut rotating electric machinery, there are efforts underway to minimize the number of connection points at coil terminals by continuously winding series coils of the same phase. Here, processing of a crossover wire between coils wound in series is required. However, if there is a sufficient space outside each bobbin, a known structure is used in which, as disclosed in, for example, JP-A-10-271718 and JP-A-11-18331, a guide is integrally provided on the outer periphery of each bobbin, and a crossover wire is routed between coils.